Method and apparatus for decoupling engine accessories

ABSTRACT

There is provided means for sequentially decoupling accessory loads from an engine in such a manner that, particularly when the engine is of optimum torque or power design, the decoupling action will not cause a sudden increase in engine torque output to be applied to the driving wheels of an automobile. Decoupling of the various engine accessories can be accomplished one at a time over a given limited range of throttle or torque demand settings or can be a gradual decoupling beginning at some predetermined throttle or torque demand setting and continuing to a condition of complete decoupling.

United States Patent Nilssen METHOD AND APPARATUS FOR DECOUPLING ENGINEACCESSORIES 8/1971 Kaye ..62/243 72 Inventor: Ole K. Nilssen, BarringtonHills, in. figx2112 2 Bums [73] Assignee: Motorola, Inc., Franklin Park,Ill. 22 Filed: Dec. 30, 1970 [571 ABSTRACT [21] Appl Nu: 102,710 Thereis provided means for sequentially decoupling accessory loads from anengme m such a manner that, particularly when the engine is of optimumtorque or [52] US. Cl ..l23/98, 62/243, 123/195 A, power design thedecoupling action Will not cause 3 123/198 R, 192/.07, 192L0 suddenincrease in engine torque output to be applied [51] il 12 g iq ggg tothe driving wheels of an automobile. Decoupling of [58] 0 the variousengine accessories can be accomplished 192/075 62/243 one at a time overa given limited range of throttle or torque demand settings or can be agradual [56] References C'ted decoupling beginning at some predeterminedthrottle UNITED STATES PATENTS or torque demand setting and continuingto a conditron of complete decoupling. 3,132,728 5/1964 Chaptois..192/.O75 X 3,186,184 6/1965 Pruitt ..192/.07 2 Claims, 6 DrawingFigures 12 1 1' y l 1 I can PATENTEDSEP 1 1912 3. s92. 00 7 FIGI FIGZ

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THRTTLE INVENTOR.

\ QLE. K. NIL SSEN BY WM,

ATTORNEYS.

METHOD AND APPARATUS FOR DECOUPLING ENGINE ACCESSORIES BACKGROUND OF THEINVENTION This invention relates generally to a method and apparatus fordecoupling engine accessories from automobile engines, or the like.

Heretofore, decoupling of an engine accessory, as for example, thecompressor of an air-conditioner, is well known and serves to provideadditional engine torque to the driving wheels of the automobile.However, such decoupling of the engine driven accessories may gosubstantially unnoticed with respect to the increase in available enginetorque, because the engines heretofore utilizing such features havebeen, for the most part, overpowered for the particular vehicle beingpropelled. For example, the large engines used in American cars are manytimes overpowered as compared to the actual power needed for theparticular load being moved. This high powered engine design serves toprovide high starting torque for fast acceleration. For example, anengine having a horse power rating of 200 horsepower or more, which isthe case for many American cars, is practically unaffected by thedecoupling action of an air-conditioner or other accessory load at thehigh speed range of the engine, and any torque increase thus produced bythe decoupling action goes substantially without notice. However if theengine were designed for optimum power capabilities for high speedsustained operation without regard to the fast acceleration desired,such engine can be made relatively small and the torque increaseobtained by decoupling the engine driven accessories is readilynoticable as a sudden increase in speed.

In the modern trend for producing automobiles which will reduce thepollution in the atmosphere, a reduction in engine size is one positiveapproach of decreasing the amount of pollutants emitted by eachautomobile. However, by reducing the engine size the maxmium amount oftorque is also reduced. Furthermore, when connecting several or moreaccessory units to be power driven by the engine, the available torqueat the driving wheels is further reduced. It is of no consequence inmost instances that the amount of torque absorbed by the accessories isnot available for power at the driving wheels. That is, during normalacceleration and at moderate sustained speeds the engine has adequatepower to supply all the torque necessary, and the throttling of thistorque by the gas pedal or throttle control is obtained uniformlythroughout the entire speed control range. However, it becomesadvantageous at the high speed, or high torque requirement conditions ofthe engine, to disconnect certain ones or substantially all of theaccessories being driven by the engine. By so disconnecting theseaccessories, when associated with engines of minimum power and torquecapabilities, the sudden reduction in load on the engine caused by thedecoupling of the accessory, will also cause a corresponding suddenincrease in torque supplied to the driving wheels of the automobile.This sudden increase is a non-throttleable condition and is undesirablebecause there is no gradual control between the two torque conditionswhich exists before and after the accessory load is removed from theengme.

SUMMARY OF THE INVENTION Accordingly, it is an object of this inventionto provide an improved accessory decoupling method and apparatus fordisconnecting one or more engine driven accessories at predeterminedtorque demand conditions.

Yet another object of this invention is to provide means for decouplinga plurality of engine accessories in sequential manner so a suddenincrease in torque is not delivered to the driving wheels of anautomobile.

Still another object of this invention is to provide a method ofdecoupling engine accessories so maximum power or torque can bedeveloped from small engines.

Briefly, the method and apparatus of this invention includes an engine,of optimum design thus being of minimum horse power, for deliveringpower to the driving wheels of an automobile over a wide range of speedand torque conditions beginning with an initial condition and uniformlyincreasing to an intermediate condition. At this intermediate condition,one or more of the various engine accessories being driven aredecoupled, either sequentially in a predetermined step-by-step fashionor linearly and uniformly at a predetermined rate, to provide acontrollable increase of torque supplied to the drivingwheels ratherthan a sudden increase. This controllable increase is at a differentrate beginning at the predetermined condition and continuing at the newrate to the maximum torque available from the engine. In one arrangementthere is provided a sequentially disconnectable switching device towhich the respective accessories are connected to receive electricalpower and are thus decoupled by the opening of different switch contactsof the device. The opening of the switch contact will de-energize aclutch or other electro-mechanical device so that during this decoupledperiod of time the torque which would otherwise be delivered to theengine accessory is now delivered to the driving wheels of theautomobile. In the alternative, a switching device can be provided witha movable contact which moves across a short circuit bus bar andtherefrom engages a resistance element uniformly to increase theresistance connected in series with the accessory energizing deviceultimately to disconnect power therefrom and remove the accessory loadfrom the engine. The plurality of accessories herein referred to may beeither a plurality of different kinds of accessories or a plurality ofdifferent stages of the same kind of accessory. That is, anair-conditioner or other relatively large load device may be formed intoseveral small sub-units of compressors which are sequentiallydisconnected one sub-unit at a time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammaticrepresentation of an automobile engine illustrating one embodiment ofthis invention;

FIG. 2 is a curve illustrating throttle setting versus torque suppliedto the driving wheels of an automobile having a relatively small enginewhen a heavy accessory load is suddenly decoupled therefrom;

FIG. 3 is a curve illustrating the decoupling of engine accessories inaccordance with one arrangement of this invention;

FIG. 4 illustrating an alternate embodiment for decoupling engineaccessories in accordance with this invention;

FIG. 5 is a curve illustrating the decoupling of engine accessories inaccordance with the alternate embodiment shown in FIG. 4; and

FIG. 6 illustrates another kind of switching device that can be used inaccordance with this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1 thereis seen an engine designated generally by reference numeral 10, and ispreferably of a type used in automobiles. The engine can be either watercooled or air cooled as desired. A carburetor 12 is provided forcontrolling the amount of fuel delivered to the engine, thusthrottleably controlling the amount of power delivered by the engine tothe drive wheels of the automobile. A setting of the engine torquedemand means will set the speed and torque conditions of the engine. Thetorque demand means is here illustrated as a gas pedal 14 connected tothe carburetor 12 by a pair of rods 15 and 16 which, in turn, areinterposed with a pair of links 17 and 18 so as to translate the slightmovement of the gas pedal in one direction to the appropriate movementof a throttling mechanism on the carburetor 12 in another direction.

Also connected to the link 18 is a switching device designated generallyby reference numeral 20. The switching device 20 is shown in a generalmanner and is used to sequentially disconnect the load of respectiveones of a plurality of engine driven accessories. That is, a movablecontactor 21 is electrically connected to a source of power, such as thebattery or alternator system of the automobile, and arcuate contacts toapply energizing current to electrical and/or electromechanical couplingmechanism of the engine accessories. These electrical and/orelectromechanical coupling mechanisms may be, for example, alternatorfield winding, clutches or solenoids, as desired. Here an arcuatecontact 22 is electrically connected to the engine accessory 23 to applyenergizing current thereto during movement of the gas pedal 14 from itsinitial power position to some intermediate power position. A secondarcuate contact segment 24 is electrically connected to an accessory 25to energize the load coupling mechanism thereof, and is correspondinglyde-energized upon further arcuate movement of the contact 21 to a secondintermediate position. Finally, a third arcuate contact 26 iselectrically connected to the coupling device of an accessory 27.Movement of the throttle to the maximum power position will thus movethe contact 21 and ultimately disconnect the last arcuate segment 26 toremoving power from the accessory 27 and then all of the accessories 23,25 and 27 will be decoupled from the engine.

The switch 20 has the arcuate contacts 22, 24 and 26 thereof insulatedone from the other and mounted to the engine for physical support butalso electrically insulated from the engine by any suitable stand off orsupport arrangement. The broken lines illustrating the movable contactor21 in an advanced position shows the disengagement of the contactor 21from the first arcuate contact 22 to de-energize the accessory 23.However, the switching device 20 may include a contact support whichextends beyond the arcuate contacts 22, 24 and 26 so that a wiper brusharrangement on the movable contactor 21, if used, will continue to besupported while electrically disconnected from the arcuate contacts.

The engine 10 is here illustrated as being of small horse power rating,as commonly found in small compact cars and many foreign cars, anddecoupling of the engine accessories will produce a substantial increasein torque delivered to the driving wheels of the automobile. This is incontrast to the larger automobiles with large and powerful engines anddecoupling of such accessories has little or no noticable effect at thepower train of the automobile.

- The gas pedal 14 is illustrated as only one means of setting a torquedemand from an engine. Any suitable throttling or power sensingarrangement can be incorporated to operate a sequential switchingarrangement and decouple the accessories 23, 25 and 27. Such decouplingmay be temporary only taking effect upon the throttle passing into thevarious intermediate ranges and automatic means may be provided torestore electrical power to the coupling devices when the engine speedincreases so that the accessories will again be driven by the engine.That is, upon acceleration of the automobile, the accessories arepreferably disconnected as described above. But as the automobile comesup to speed and thus torque demands decrease, the accessories may beagain connected to the engine one at a time in reverse sequence or allat the same time.

The switching device 20 may be of any suitable kind, as for example, aplurality of limit switches engaging a mechanical link at various pointsthrough its movement or it may be done electronically with sensingelements positioned on the linkage between the gas pedal and thecarburetor to sense its movement.

FIG. 2 illustrates the throttle versus torque curve and is designated byreference numeral 30. This curve shows a sudden rise 31 in torquedelivered to the driving wheels of an automobile when the relativelylarge load accessories are suddenly disconnected from the engine. Thisincrease in torque is uncontrollable and undesirable as it is notdistributed over a range of throttle settings.

FIG. 3, illustrates the throttle versus torque conditions produced bythe engine and decoupling arrangement such as that shown in FIG. 1. Thecurve 32 continuously increases with the throttle setting to anintermediate condition 33 whereupon the first engine acc essory isdecoupled and only a small portion of the torque is then applied to thedriving'wheels. As the throttle is further advanced to a secondintermediate position, a torque increase designated by reference numeral34 is applied to the driving wheels. A final throttle setting willincrease the torque as designated by reference numeral 35, and thiscondition then applies maximum torque to the driving wheels. Thisstep-by-step function will prevent a sudden surge of torque as shown inFIG. 2.

When utilizing this arrangement, various engine accessories can bedecoupled for example, an air-conditioning compressor, an electricheating alternator, the standard power and battery-charging alternator,the cooling fan, the water pump and so on. However, such accessories asdesignated herein may also be fractional parts of one accessory whichprovides a large load. For example, an air-conditioner having severalsmall compressors rather than one large compressor can have each of thesmaller compressors decoupled in a sequential manner.

Referring now to FIG, 4, there is seen an alternate embodiment of thisinvention and only the switching mechanism thereof is illustrated. Herea switching device 40 is shown with a movable contactor 41 engaging astationary arcuate contact segment 42 which ultimately leads into a wirewound resistance element 43, or any other suitable variable impedanceelement. As the movable contactor 41, which is connected to the throttlelinkage of the automobile, moves across the arcuate contact 42, fullelectrical power is continuously applied to the accessory or accessoriesthrough a line 45. At some intermediate position of the contact 41,electrical power through the line 45 is restricted by the amount ofresistance inserted in the line as the movable contact 41 goes acrossthe resistance element 43. This change in resistance thus decreases theamount of load being absorbed by the accessory, this being true in thecase in an alternator or generator arrangement wherein excitationcurrent is supplied through the switching device 40, so that the torquedelivered to the driving wheels gradually increases. This is bestillustrated in FIG. 5 which shows a throttle versus torque curve 50 andat an intermediate position 51, this point corresponding to the pointwhere movable contact 41 initially engages the resistance element 43,the torque delivered to the driving wheels increases uniformly with gaspedal movement but at a different rate as indicated by the line segment52. This arrangement has particular utility when disconnecting, forexample, an alternator by merely decreasing the amount of powerdelivered to the excitation winding of the alternator. Thus, reducingthe excitation current to the alternator by increasing the seriesresistance therewith will reduce the amount of torque absorbed by thealternator and this torque is delivered to the driving wheels of theautomobile.

Seen in FIG. 6 is an alternate form of switching device which can beused in accordance as part of the apparatus of this invention. Theswitching device may be mounted to any suitable support on or near theengine 10 and it has a shaft 60 for rotation in the direction of thearrow. Upon actuation of the accelerator pedal 14, and throughappropriate linkages, the shaft 60 rotates an insulated body 62 securedthereto which, in turn, has a radially outwardly conductive segment 64.The conductive segment 64 engages a series of stationary contacts 66, 68and 70 which are arranged for connection to the accessories 23, 25 and27, respectively. As the trailing edge 64a of the conductive segment 64disengages the stationary contacts, the accessory connected to therespective contact is de-energized and the load thus removed from theengine. Many other suitable switching arrangements may be incorporatedto form the features f this invention.

What has been described is a simple and effective means for sequentiallyor uniformly removing the load of engine accessories from mechanicalconnection with the engine during certain load demand conditions so thatthe torque which would otherwise b3 absorbed b these accessories is nowavailable at the r1 vmg whee s of the automobile to provide additionalpower for acceleration. Such decoupling action, either the sequentialstep-by-step function or the linear function, is substantially uniformof the range of decoupling. Accordingly, variations and modifications ofthis invention may be affected without departing from the spirit andscope of the novel concepts disclosed and claimed therein.

I claim:

1. A method of decoupling a plurality of individual engine accessorymeans from an engine which is to operate over a wide range of enginespeeds under various torque conditions, comprising the steps of, settingof a torque demand means to select the desired engine speed and torqueconditions, said speed and torque conditions being uniformly variableover a range beginning from its initial condition and continuing untilthe engine produces maximum deliverable torque, step-by-step decouplingof a plurality of said individual accessory means each at a differenttime sequence beginning at said initial condition and continuing suchstep-by-step decoupling action until all engine accessories that are tobe decoupled are in fact decoupled and the engine produces maximumdeliverable torque.

2. An apparatus for decoupling engine accessory means comprising incombination an engine for delivering power over a range of speed andtorque conditions beginning with an initial condition and uniformlyvariable to an intermediate condition, a torque demand means selectivelyto increase engine power uniformly through the entire range of speed andtorque conditions, a switching mechanism connected to said torque demandmeans for switchably disconnecting respective different ones of theaccessory means in a predetermined sequence beginning at saidintermediate condition and continuing to a maximum speed and torquecondition, and decoupling means responsive to said switching mechanismfor gradually decoupling engine accessory means until all such accessorymeans that are to be decoupled are in fact decoupled thus allowing theengine to produce maximum torque.

1. A method of decoupling a plurality of individual engine accessorymeans from an engine which is to operate over a wide range of enginespeeds under various torque conditions, comprising the steps of, settingof a torque demand means to select the desired engine speed and torqueconditions, said speed and torque conditions being uniformly variableover a range beginning from its initial condition and continuing untilthe engine produces maximum deliverable torque, step-by-step decouplingof a plurality of said individual accessory means each at a differenttime sequence beginning at said initial condition and continuing suchstep-by-step decoupling action until all engine accessories that are tobe decoupled are in fact decoupled and the engine produces maximumdeliverable torque.
 2. An apparatus for decoupling engine accessorymeans comprising in combination an engine for delivering power over arange of speed and torque conditions beginning with an initial conditionand uniformly variable to an intermediate condition, a torque demandmeans selectively to increase engine power uniformly through the entirerange of speed and torque conditions, a switching mechanism connected tosaid torque demand means for switchably disconnecting respectivedifferent ones of the accessory means in a predetermined sequencebeginning at said intermediate condition and continuing to a maximumspeed and torque condition, and decoupling means responsive to saidswitching mechanism for gradually decoupling engine accessory meansuntil all such accessory means that are to be decoupled are in factdecoupled thus allowing the engine to produce maximum torque.